Patent Literature 1 discloses a Raman scattered light enhancement device formed such that stimulated Raman scattering can be generated in a slab-type two-dimensional photonic crystal where a number of holes are formed in a slab made of silicon so as to have a two-dimensional periodic structure. The Raman scattered light enhancement device of Patent Literature 1 has an in-plane heterostructure formed by combining two-dimensional photonic crystals each having different structural parameters, and realizes optical confinement using a difference in mode gaps due to the difference of the structural parameters.
In the Raman scattered light enhancement device of Patent Literature 1, there is provided an optical resonator configured of a waveguide made up of a linear defect formed in the photonic crystal, and there are provided two reflection parts so as to realize resonant modes for each of a wavelength of incident light and a wavelength of Raman scattered light of an object medium.